1. Field of the Invention:
The invention relates to a catalyst plate, and more particularly, to a catalyst plate for nitrogen oxide reduction in exhaust gases, which is molded from granular Fe.sub.2 O.sub.3 catalyst material and a binder.
2. Description of the Prior Art:
Attempts have already been made to manufacture Fe.sub.2 O.sub.3 catalyst material using sulphuric acid or phosphoric acid as binders. It has thereby been shown that only the sulphuric acid binding leads to a high activity, but it also produces an excessive sensitivity to water, which causes the plates to absorb water and become soft. On the other hand, the phosphoric acid bonding reduces activity, but produces hard plates which are not sensitive to water. Mixtures of phosphoric acid and sulphuric acid lead to a catalyst action which is not always satisfactory. Even the saturation of catalyst plates containing a phosphoric acid binder with sulphuric acid, and vice-versa, results in only moderate improvements.
Catalysts are known, specifically, for example, catalysts containing Fe.sub.2 O.sub.3, Cr.sub.2 O.sub.3 or V.sub.2 O.sub.5. In terms of their action, however, these catalysts leave something to be desired.
Some examples of catalytic technology are found in U.S. Pat. No. 4,259,312, entitled "Process And Apparatus For Catalytically Reacting A Reducing Gas And Water Vapor"; U.S. Pat. No. 4,235,604 entitled "Method For Processing Coke Oven Gas": and U.S. Pat. No. 4,049,777, entitled "Method Of Waste Gas Treatment", all of which are assigned the same assignee as the instant application.
Further examples of catalytic technology are found in U.S. Pat. No. 4,448,895, entitled "Process For Preparation Of Catalyst For Cleaning Exhaust Gases And Catalyst Prepared For The Process", and U.S. Pat. No. 4,503,162, entitled "Catalyst Systems For The Conversion Of Gases".
Examples of reactivation of catalysts useful in nitrogen oxide removal are described in U.S. Pat. No. 4,044,102, entitled "Method For Treating Exhaust Gases", and U.S. Pat. No. 4,043,939, entitled "Reactivation Of Catalysts Useful For Nitrogen Oxide Removal." All of the above-cited patents are incorporated herein by reference as if the texts thereof were fully set forth herein.